Packer

ABSTRACT

A packer that is usable with a well includes a resilient seal element and a support member. The resilient seal element is adapted to radially expand in response to the longitudinal compression of the element. The support member is at least partially surrounded by the seal element and is adapted to radially expand with the seal element to support the element. The support sleeve is substantially harder than the seal element.

This application claims the benefit pursuant to 35 U.S.C. § 119(e) toU.S. Provisional Patent Application Ser. No. 60/595,997 entitled,“PACKER ELEMENT WITH SUPPORT,” filed on Aug. 23, 2005, which is herebyincorporated in reference in its entirety.

BACKGROUND

The invention generally relates to a packer.

Hydrocarbon fluids, such as oil and natural gas, are obtained from asubterranean geologic formation, referred to as a reservoir, by drillinga well that penetrates the hydrocarbon-bearing formation. Once awellbore has been drilled, the well must be completed beforehydrocarbons can be produced from the well. A completion involves thedesign, selection, and installation of equipment and materials in oraround the wellbore for conveying, pumping, or controlling theproduction or injection of fluids. After the well has been completed,production of oil and gas can begin.

In such well completion operations, packers are used to prevent fluidflow through an annulus formed by a tubing within the well and the wallof the wellbore or a casing. The packer is generally integrallyconnected to the tubing, using, for example, means such as a threadedconnection, a ratch-latch assembly, or a J-latch, all of which are wellknown in the art. The tubing/packer connection generally establishes theseal for the inner radius of the annulus. The seal for the outer radiusof the annulus is generally established by a deformable element such asrubber or an elastomer. A compressive force is generally applied to thedeformable element, causing it to extrude radially outward. The elementextends from the outer portion of the packer to the wellbore wall orcasing and seals between those structures.

SUMMARY

In an embodiment of the invention, a packer that is usable with a wellincludes a resilient seal element and a support member. The resilientseal element is adapted to radially expand in response to thelongitudinal compression of the element. The support member is at leastpartially surrounded by the seal element and is adapted to radiallyexpand with the seal element to support the element. The support sleeveis substantially harder than the seal element.

In another embodiment of the invention, a technique that is usable witha well includes compressing a resilient seal element to cause the sealelement to radially expand. The technique includes in concert with theradial expansion of the seal element, deforming a material that issubstantially harder than the seal element to support the seal element.

Advantages and other features of the invention will become apparent fromthe following drawing, description and claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram of a well according to an embodiment ofthe invention.

FIG. 2 is a schematic diagram depicting a seal assembly of the packer ofFIG. 1 according to an embodiment of the invention.

FIG. 3 depicts the seal assembly when the packer is set according to anembodiment of the invention.

FIGS. 4, 5, 6 and 7 depict seal assemblies according to otherembodiments of the invention.

DETAILED DESCRIPTION

A packer is a device that is used in an oilfield well to form a seal forpurposes of controlling production, injection or treatment. The packeris lowered downhole into the well in an unset state, and once in theappropriate position downhole, the packer is set, which means a seal ofthe packer radially expands to seal off an annular space. As an example,for a mechanically-set packer, a tubular string that extends from thesurface to the packer may be moved pursuant to a predefined pattern toset the packer. For a hydraulically-set packer, fluid inside the tubularstring may be pressurized from the surface, to create a tubing pressuredifferential to set the packer.

In its set state, the packer anchors itself to the casing wall of thewell (or to the wellbore wall in an uncased or open well) and forms aseal in the annular region between the packer and the interior surfaceof the casing wall. This seal subdivides the annular region to form anupper annular region above the packer that is sealed off from a lowerannular region below the packer. The packer also forms a seal forconduits that are inserted through the packer between the upper andlower annular regions. As examples, one of these conduits maycommunicate production fluid from a production zone that is locatedbelow the packer, one of the conduits may communicate control fluidthrough the packer, one of the conduits may house electrical wiring fora submersible pump, allow production or injection through two differentreservoir zones, and so forth.

FIG. 1 depicts a well 10 (a subterranean or subsea well) that includes apacker 20 in accordance with an embodiment of the invention. The packer20 may be connected to a tubular string 16 that extends downhole intothe well. The packer 20 forms an annulus seal with the interior surfaceof a wall of a casing string 12 that circumscribes the packer 20 andlines a wellbore 11. The wellbore 11 may be uncased in some embodimentsof the invention. Additionally, the wellbore 11 may be a vertical or alateral wellbore, depending on the particular embodiment of theinvention.

The packer 20 includes at least one seal assembly 24 to form the annularseal and at least one set of slips 22 to anchor the packer 20 to thecasing string 12. In this manner, when run into the well, the sealassembly 24 and the slips 22 are radially retracted to allow passage ofthe packer 20 through the central passageway of the casing string 12.However, when the packer 20 is in the appropriate downhole position, thepacker 20 is set to place the packer 20 in a state in which the sealassembly 24 and slips 22 are radially expanded. When radially expanded,the slips 22 grip the interior surface of the wall of the casing string12 to physically anchor the packer 20 in position inside the well. Theradial expansion of the seal assembly 24, in turn, seals off the annularspace between the string 16 and the casing string 12 to form a sealedannular region above the seal assembly 24 and a sealed annular regionbelow the seal assembly 24.

In some embodiments of the invention, the packer 20 may behydraulically-actuated for purposes of controlling the packer 20 fromthe surface of the well to set the packer 20. This means that pressuremay be communicated through fluid inside the string 16 to the packer 20.In response to this pressure reaching a predefined threshold level,pistons (not shown in FIG. 1) move to radially expand the slips 22 andapply compressive forces on the seal assembly 24 to radially expand theassembly 24. A retention mechanism of the packer 20 serves to hold thepacker 20 in the set state when the pressure that is used to set thepacker 20 is released.

One or more mandrels 21, or tubular members, may extend through thepacker 20 for purposes of providing communicating paths through thepacker 20. Depending on the particular application of the packer 20, aparticular mandrel 21 may contain one or more communication paths, suchas paths to communicate production fluid, electrical lines, or controlfluid through the packer 20. For example, in a particular application, asingle mandrel 21 may extend through the packer 20 for purposes ofcommunicating production fluid from a tubular string 23 located belowthe packer 20 to the string 16 located above the packer 20. However, inother applications, more than one mandrel 21 may be extended through thepacker 20. Thus, one mandrel 21 may be used for purposes ofcommunicating electrical or hydraulic lines, for example, and anothermandrel 21 may be used for purposes of communicating production fluidthrough the packer 20.

The packer 20 may be retrievable, and thus may include a releasemechanism that when engaged, releases the retention mechanism of thepacker 20 to radially retract the slips 22 and seal assembly 24 topermit retrieval of the packer 20 to the surface of the well.

The packer 20 establishes two general seals: an interior seal betweenthe interior of the packer 20 and the exterior of the one or moremandrels 21 that are extended through the packer 20 and an exterior sealbetween the exterior of the packer 20 and the interior surface of thewall of the casing string 12 (or the wellbore wall in alternativeembodiments). The seal assembly 24 includes a resilient seal element(such as one or more elastomer or rubber sleeves, or rings) forestablishing the seal between the packer exterior and the casing 12 (orwellbore wall).

In general, as the requirements for packer designs tend towards largerand larger inner diameters through the packer, the annular seal elementof the packer is forced to become thinner and thinner. Additionally,there may also desire to cover multiple casing weights with one size ofpacker, leading to larger gaps that must be bridged off by the annularseal element. Bridging off a large gap with a thin element may be verydifficult, unless the rubber is supported. Embodiments of the inventionthat are described herein include a packer that has a resilient sealelement, which has a support that is fabricated from a hardenedmaterial.

In the context of this application, a “hardened material” means amaterial that has a substantially greater resistance to deformationrelative to the seal element of the packer. For example, in someembodiments of the invention, the hardened material may be a metal thathas substantially more resistance to deformation than an elastomer orrubber material that forms the seal element. Alternatively, inaccordance with other embodiments of the invention, the hardenedmaterial may be a composite or plastic material, which has substantiallymore resistance to deformation that an elastomer or rubber material thatforms the seal element. Furthermore, in accordance with otherembodiments of the invention, the hardened material may be a combinationof the above-mentioned materials. Thus, many variations are contemplatedand are within the scope of the appended claims.

As a more specific example, for some embodiments of the invention, thehardened material is a soft metal, such as low carbon steel or copper,in accordance with some embodiments of the invention. However, inaccordance with other embodiments of the invention, the hardenedmaterial may be a relatively resilient material. For example, inaccordance with some embodiments of the invention, the hardened materialmay be a metallic spring material. Thus, many variations are possibleand are within the scope of the appended claims.

FIG. 2 depicts a more detailed section 50 (see FIG. 1) of the packer 20in accordance with some embodiments of the invention. As shown in FIG.2, the packer 20 includes sleeves, or gages 54 and 55 (also called“thimbles”), which are designed to longitudinally compress the sealassembly 24 (which is disposed in between) to radially expand theassembly 24 when the packer 20 is set. It is noted that FIG. 2 depictsthe packer 20 in its unset state.

In general, the seal assembly 24 includes a resilient seal element thatmay be formed from multiple seal sleeves, or rings, such as upper 56,middle 60 and lower 64 seal rings. The seal rings 56, 60 and 64generally circumscribe the inner mandrel 16 of the packer 20 and may beformed from a rubber or an elastomer material (as examples). It is notedthat the seal assembly 24 may include fewer or more seal rings,depending on the particular embodiment of the invention.

As also depicted in FIG. 2, the seal assembly 24 may include upper 88and lower 90 metallic shoes for purposes of minimizing the longitudinalextrusion of the seal element 24 when the packer 20 is set. In thepacker's unset state, the upper shoe 88 generally conforms to the upperedge of the seal ring 56 and is located between the upper edge of theseal ring 56 and the upper gage 54; and the lower shoe 90 generallyconforms to the lower edge of the lower seal ring 64 and is locatedbetween this lower edge and the lower gage 55.

In addition to the resilient seal element, the seal assembly 24 includesa hardened (relative to the seal rings 56, 60 and 64) support sleeve 80that is located between the resilient seal element and the mandrel 16.As a more specific example, as depicted in FIG. 2, in some embodimentsof the invention, the support sleeve 80 may be located (as an example)between the middle seal ring 60 and the outer surface of the mandrel 16.The support sleeve 80, which may have a substantially thinner radialthickness than the middle seal ring 60 (before the packer 20 is set), isdesigned to be radially expanded (and deformed) with the seal rings 56,60 and 64 so that the sleeve 80 supports the seal rings 56, 60 and 64 intheir radially-expanded states. Although FIG. 2 depicts the supportsleeve 80 as being located radially inside the middle seal ring 60, inaccordance with other embodiments of the invention, the support sleeve80 may longitudinally extend inside all or part of the upper 56 andlower 64 seal rings (as another example). Therefore, many variations arepossible and are within the scope of the appended claims.

The support sleeve 80 may or may not be bonded to the middle seal ring60, depending on the particular embodiment of the invention. Forembodiments of the invention in which the support sleeve 80 is bonded tothe middle seal ring 60, all or only part of the outer surface of thesupport sleeve 80 may be bonded to the inner surface of the middle sealring 60. It is noted that depending on the particular embodiment of theinvention, the support sleeve 80 may be bonded to all, part or none ofthe upper 56 and lower 64 seal rings.

In some embodiments of the invention, the support sleeve 80 includes anannular crimped section 82 at its longitudinal midpoint, which radiallyextends away from the outer surface of the mandrel 16. The crimpedsection 82 configures the support sleeve 80 to bend at the section 82during the radial expansion of the seal assembly 24, as depicted in FIG.3, which shows a section 95 of FIG. 2 when the packer 20 is set.Referring to FIG. 3, in the radially expanded state of the seal assembly24, the seal rings 56, 60 and 64 are radially expanded and deformed toat least partially contact the inner surface of the casing 12. As alsoshown in FIG. 3, the support sleeve 80 is also radially expanded anddeformed to support the seal rings 56, 60 and 64. The shoes 88 and 90minimize longitudinal extrusion of the seal element, in this state ofthe packer 20.

Referring back to FIG. 2, in accordance with some embodiments of theinvention, the region between the inner surface of the crimped section82 and the outer surface of the mandrel 16 may be a void space. However,in accordance with other embodiments of the invention, this space may befilled with a seal element that partially or totaling conforms to theboundaries of the space before the packer 20 is set.

FIG. 4 depicts an exemplary section 100 of another packer in accordancewith another embodiment of the invention. The section 100 is to becompared to the corresponding section 95 of the packer 20. In general,the packer has the same overall design as the packer 20, except the sealassembly of this packer includes a single seal ring 124 (made fromelastomer or rubber, for example) and an inner o-ring 110 behind asupport sleeve 112 (made from a hardened material relative to the sealring 124). The support sleeve 112 extends over the entire inner surfaceof the seal ring 124. The support ring 112 also includes a crimpedsection 114 that, in the unset state of the packer 20, radially extendsaway from the outer surface of the mandrel 16. The crimped section 114creates a void 116 that receives the o-ring seal 110. Other seals may belocated inside the space 116, in accordance with other embodiments ofthe invention.

Referring to FIG. 5, in accordance with other embodiments of theinvention, another packer, which is illustrated by an exemplary section150 (to be compared to sections 95 and 100), includes expandable rings160 and 178 that are located between the gages and a single seal ring190. More specifically, an upper expandable ring 160 is located betweenan upper gage 154 and an upper edge of the seal ring 190. The upper gage154 may include a sloped, or beveled, surface 156 for purposes ofslidably engaging with the upper expandable seal ring 160. Likewise, alower expandable seal ring 178 may be located between a lower gage 164and the lower surface of the seal ring 190. Similar to the upper gage154, the lower gage 164 includes a sloped, or beveled, surface 166 forpurposes of slidably engaging the lower expandable ring 178.

As also shown in FIG. 5, the packer includes a support sleeve 180 (madefrom a hardened material) that extends over the entire surface of theseal ring 190 for purposes of providing support to the ring 190 for theset state of the packer. The seal ring 180 includes a crimped section182 that is predisposed to cause the support ring 180 to radially expandat the section 182 during the setting of the packer, similar to thesupport rings 80 and 112 that are described above.

As yet another variation, FIG. 6 depicts an exemplary section 200 of apacker in accordance with another embodiment of the invention. As shown,the packer includes garter springs that are located between the gagesand the seal assembly. More specifically, an upper garter spring 210 islocated between an upper gage 202 and the upper edge of a seal ring 230.A lower garter spring 212 is located between the upper edge of a lowergage 220 and the lower edge of the seal element 230. Additionally, thepacker includes a support sleeve 232 (made from a hardened material)that is located over the entire inner surface of the seal ring 230between the seal ring 230 and the outer surface of the mandrel 16; andthe sleeve 232 includes a crimped portion 234 to predispose the sleeve232 to radially expand at the section 234 during the setting of thepacker.

As yet another example, FIG. 7 depicts an exemplary section 250 of apacker in accordance with another embodiment of the invention. Thesection 250 is similar to the section 50 (see FIG. 2) (with likereference numerals being used), with the following differences. Inparticular, the packer includes support rings 260 and 270 that arelocated at the ends of the seal assembly 24 for purposes of minimizinglongitudinal extrusion of the packer's seal element. The support ring260 is located between the upper shoe 88 and the upper gage 54; and thelower ring 270 is located between the lower gage 55 and the shoe 90.

Each of the rings 260 and 270 has a V-shaped cross-section and providessupport to minimize longitudinal extrusion of the seal element (sealrings 56, 60 and 64) when the packer is set. More specifically, when thepacker is set, the V-shaped rings 260 and 270 each flatten to besubstantially horizontal and rise above the gauge diameter, therebyminimizing the extrusion gap and supporting the seal element.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art, having the benefit ofthis disclosure, will appreciate numerous modifications and variationstherefrom. It is intended that the appended claims cover all suchmodifications and variations as fall within the true spirit and scope ofthis present invention.

1. A packer usable with a well, comprising: a resilient seal elementadapted to radially expand in response to a longitudinal compression ofthe seal element; and a support member at least partially surrounded bythe seal element and being substantially harder than the seal element,the support member adapted to radially expand with the seal element tosupport the seal element.
 2. The packer of claim 1, wherein the supportmember comprises a sleeve circumscribed by the seal element.
 3. Thepacker of claim 1, wherein the support member has a first radialthickness that is substantially smaller than a second radial thicknessof the seal element.
 4. The packer of claim 1, wherein the support hassubstantially more resistance to deformation than the seal element. 5.The packer of claim 1, wherein the seal element comprises at least oneof a rubber and an elastomer.
 6. The packer of claim 1, wherein themember comprises a metal.
 7. The packer of claim 1, wherein the supportmember is bonded to the resilient seal element.
 8. The packer of claim1, further comprising: an inner tubular member of the packer having anouter surface, wherein the support member comprises first regions thatclosely adhere to the outer surface before the longitudinal compressionof the seal element and a second region that extends radially away fromthe outer surface before the longitudinal compression of the sealelement.
 9. The packer of claim 1, further comprising: another sealelement at least partially circumscribed by the support member.
 10. Thepacker of claim 1, further comprising: a gage adapted to longitudinallycompress the seal element; and at least one expandable seal assemblylocated between the gage and the seal element.
 11. The packer of claim1, further comprising: a gage adapted to longitudinally compress theseal element; and at least one spring located between the gage the sealelement.
 12. The packer of claim 1, further comprising: a gage adaptedto longitudinally compress the seal element; and at least one radiallyexpandable ring located between the gage and the seal element.
 13. Amethod usable with a well, comprising: providing a resilient sealelement adapted to radially expand in response to longitudinalcompression of the seal element; and radially inside the seal element,disposing a support member adapted to radially expand with the sealelement to support the seal element, the support member beingsignificantly harder than the seal element.
 14. The method of claim 13,further comprising: selecting the support member to have substantiallymore resistance to deformation than the resilient seal element.
 15. Themethod of claim 13, wherein the resilient seal element comprises atleast one of a rubber and an elastomer.
 16. The method of claim 15,wherein the support member comprises a metal.
 17. The method of claim13, further comprising: bonding the support member to the seal element.18. A method usable with a well, comprising: compressing a resilientseal element to cause the seal element to radially expand; and inconcert with the radial expansion of the seal element, deforming amaterial that is substantially harder than the seal element to supportthe seal element.
 19. The method of claim 18, wherein the support memberhas substantially more resistance to deformation than the seal element.20. The method of claim 18, wherein the seal element comprises at leastone of a rubber and an elastomer.
 21. The method of claim 13, whereinthe member comprises at least one of a metal, a composite and a plastic.22. A system usable with a well, comprising: a string; and a packerconnected to the string, the packer comprising: a resilient seal elementadapted to radially expand in response to a longitudinal compression ofthe seal element; and a support member at least partially surrounded bythe seal element and being substantially harder than the seal element,the support member adapted to radially expand with the seal element tosupport the seal element.
 23. The system of claim 22, wherein thesupport member has substantially more resistance to deformation than theseal element.